@fpc wrote:
The effect of missing the nine month deadline here is that each beneficiary making the disclaimer is treated as making a gift to the fifth sibling in the amount of the value of the share of the property that is being transferred. It is exactly the same tax result that would occur if the four siblings did quit claim deeds rather than disclaimers."
I would interpret current federal law as stating that a missed deadline is tantamount to not having filed a valid disclaimer (note the term "qualified disclaimer" is used in the statute).
As a result, the interest would vest in the beneficiary(ies) without a qualified disclaimer. Obviously, each beneficiary would then be free to gift the interest the beneficiary acquired to any third party and, if over the annual exclusion, would be required to file a gift tax return.
